Memory tags may most generally be considered as memory devices that are not self-powered but which provide input and or output when powered (rather than only when placed in an appropriate drive, such as a CD). Such memory tags may thus be used in situ in any physical environment where they can be powered.
Existing memory tags typically comprise a transponder (an electrical device designed to receive a specific signal and automatically transmit a specific reply)—Radio Frequency Identification (RFID) tags are one such form of tag. RFID tags come in many forms but all comprise an integrated circuit including a memory, in which in use information can be stored, and a coil which enables the circuit to be interrogated by a reader which also powers it by means of an inductive (wireless) link. Until recently RFID tags have been quite large, due to the frequency they operate at (13.56 MHz) and the size of coil they thus require, and have had very small storage capacities. Such RFID tags have tended to be used in quite simple applications, such as for file tracking within offices or in place of or in addition to bar codes for product identification and supply chain management.
Much smaller RFID tags have also been developed, operating at various frequencies. For example Hitachi-Maxell have developed “coil-on-chip” technology in which the coil required for the inductive link is on the chip rather than attached to it This results in a memory tag in the form of a chip of 2.5 mm square, which operates at 13.56 MHz. This chip is capable of both being read and being written to. In addition Hitachi has developed a memory tag they call a “mu-chip” which is a chip of 0.4 mm square and operates at 2.45 GHz. This chip is written with data during the manufacturing process in Read-Only-Memory (ROM), but is small enough to be embedded in paper.
Many uses of memory tags are already known, as indicated above. However, as the storage capacity of the memory tags increases their uses are becoming more to do with data storage rather than simply as a convenient place to store a single number or very limited data. For example Eastman Kodak Company has proposed a range of applications relating to images, presumably intended for use with photographic images, whereby data relating to the images is stored in RFID tags connected to the substrate on which the photographs are printed, e.g. as disclosed in EP 1 076 316 A2 and U.S. Pat. No. 6,363,239 B1.
Many forms of readers and reader/writers for communication with memory tags are also known. Some are wireless and hand held but simply display the limited information read from the tag on a small screen, such as those used to read the tags implanted into pet animals. Others, such as those manufactured by TEK Industries, Inc. and apparently intended for use in supply chain management, are wireless and hand held and store the information from a number of memory tags in internal memory before being downloaded to computer using a cradle or alternative connection technique using additional apparatus. Other readers, also available from TEK Industries, Inc. and capable of writing as well as reading, couple to a personal digital assistant (PDA) to form a single hand held unit and communicate (for example the TEK Stationary Reader) immediately with the PDA. Yet other forms of readers and reader/writers are known which are integral with large fixed equipment such as printers, or are simply hardwired to a computer.
The invention provides assistance in making practical use of the developments in RFID technology, and indeed in any other memory tag technologies, in relation to the ease with which data stored in the memory tags may be read and transferred elsewhere.